diff --git a/README.md b/README.md
index e387447..09343eb 100644
--- a/README.md
+++ b/README.md
@@ -77,7 +77,7 @@ The fastest way to setup a project is to use `pycalver init`.
 ```shell
 $ pip install pycalver
 ...
-Installing collected packages: click pathlib2 typing toml six pycalver
+Installing collected packages: click pathlib2 typing toml pycalver
 Successfully installed pycalver-202007.36
 
 $ pycalver --version
diff --git a/requirements/pypi.txt b/requirements/pypi.txt
index 0bd5192..9dcff45 100644
--- a/requirements/pypi.txt
+++ b/requirements/pypi.txt
@@ -11,5 +11,4 @@ pathlib2
 typing; python_version < "3.5"
 click
 toml
-six
 lexid
diff --git a/src/pycalver/config.py b/src/pycalver/config.py
index e5b41a8..57223f6 100644
--- a/src/pycalver/config.py
+++ b/src/pycalver/config.py
@@ -11,7 +11,6 @@ import logging
 import datetime as dt
 import configparser
 
-import six
 import toml
 import pathlib2 as pl
 
@@ -168,7 +167,7 @@ def _parse_cfg(cfg_buffer: typ.IO[str]) -> RawConfig:
 
     for option, default_val in BOOL_OPTIONS.items():
         val: OptionVal = raw_cfg.get(option, default_val)
-        if isinstance(val, six.text_type):
+        if isinstance(val, (bytes, str)):
             val = val.lower() in ("yes", "true", "1", "on")
         raw_cfg[option] = val